1. Field of the Invention
The present invention relates to a control device for a stepping motor and a control method for a stepping motor, and particularly, to a control device for a stepping motor and a control method for a stepping motor, which move a rotor to a predetermined position during activation period or stop period of the stepping motor.
2. Description of the Related Art
A stepping motor is excited by applying an excitation current to multiple coils, whereby a rotor is driven to rotate in steps. During activation period of the stepping motor, in general, a hold current for attracting the rotor positioned at an arbitrary position to a position (an initial position) facing a stator is applied to the coils, and after vibration of the rotor at the initial position stops, a driving current is applied, whereby normal driving is performed. Since the stepping motor is driven as described above, it is possible to prevent hunting of the stepping motor and to surely activate the stepping motor.
For example, JP-A-2012-016122 discloses a motor control method during activation period, where a hold current is slowly increased during start period.
According to this control method, since a rotor of a stepping motor slowly moves to an initial position during activation period, it is possible to suppress generation of vibration sound and impact sound.
Incidentally, although a method of controlling a stepping motor as disclosed in JP-A-2012-016122 is used, it is desired to further suppress generation of vibration sound, impact sound, and the like during driving period of the stepping motor.